> On Aug 19, 2020, at 5:29 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Tue, Aug 18, 2020 at 05:26:26PM -0400, Chuck Lever wrote:
>>
>>> On Aug 17, 2020, at 6:20 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>
>>> On Sun, Aug 16, 2020 at 04:46:00PM -0400, Chuck Lever wrote:
>>>
>>>> In order of application:
>>>>
>>>> 5920afa3c85f ("nfsd: hook nfsd_commit up to the nfsd_file cache")
>>>> 961.68user 5252.40system 20:12.30elapsed 512%CPU, 2541 DELAY errors
>>>> These results are similar to v5.3.
>>>>
>>>> fd4f83fd7dfb ("nfsd: convert nfs4_file->fi_fds array to use nfsd_files")
>>>> Does not build
>>>>
>>>> eb82dd393744 ("nfsd: convert fi_deleg_file and ls_file fields to nfsd_file")
>>>> 966.92user 5425.47system 33:52.79elapsed 314%CPU, 1330 DELAY errors
>>>>
>>>> Can you take a look and see if there's anything obvious?
>>>
>>> Unfortunately nothing about the file cache code is very obvious to me.
>>> I'm looking at it....
>>>
>>> It adds some new nfserr_jukebox returns in nfsd_file_acquire. Those
>>> mostly look like kmalloc failures, the one I'm not sure about is the
>>> NFSD_FILE_HASHED check.
>>>
>>> Or maybe it's the lease break there.
>>
>> nfsd_file_acquire() always calls fh_verify() before it invokes nfsd_open().
>> Replacing nfs4_get_vfs_file's nfsd_open() call with nfsd_file_acquire() adds
>> almost 10 million fh_verify() calls to my test run.
>
> Checking out the code as of fd4f83fd7dfb....
>
> nfsd_file_acquire() calls nfsd_open_verified().
>
> And nfsd_open() is basically just fh_verify()+nfsd_open_verified().
>
> So it doesn't look like the replacement of nfsd_open() by
> nfsd_file_acquire() should have changed the number of fh_verify() calls.
Agreed, the increase is a little mysterious.
> --b.
>
>>
>> On my server, fh_verify() is quite expensive. Most of the cost is in the
>> prepare_creds() call.
--
Chuck Lever
